1. Field of the Invention
The present invention relates to a network device and an information sharing system. The invention particularly relates to the information sharing system that does not require a server.
2. Description of the Related Art
A general system that shares the same information between a plurality of devices is a host-client system represented by a server system. In this system, a host device is prepared in a plurality of devices to retain and manage all or some data, and the other client devices perform command operations so that uniformed network maintenance is carried out.
One or more host devices are always required for realizing the host-client system, and all loads are put on this device to be a host. Further, when the host is shut down or communication with the host is interrupted for some reason, the system cannot be used until the interruption is removed.
In order to search for information quickly and efficiently and obtain the information without a server, Japanese Patent Application Laid-Open No. 2004-192103 discloses a P2P network in which a PC structuring the P2P network includes a distribution unit for distributing contents of a self information table to another PC, a collecting unit for collecting contents of an information table of another PC, an updating unit for updating information so that the contents of the information tables of all the PCs are the same as each other, and an obtaining unit for obtaining information and data selected in the information table from another PC.
In the conventional technique, the contents of the information table of another PC are collected and information is updated so that the information tables of all PCs have the same contents, but communication traffic increases when the contents of the information tables of another PC are simultaneously collected, a load for processing the collected information tables increases. Therefore, in case that a CPU performance of a PC is low, the processing requires a long time or the collecting might be disabled. Further, even if the information table is shared by all PCs, in case that the contents of the information table are changed thereafter, it is necessary to reflect the changed contents in all the information tables efficiently.